Signal



P. H. CHASE June 8, 1937.

SIGNAL Filed Sept. 15, 1933 6 Sheets-Sheet 1 FIGI.

Has.

Juhe 8,- 1937. P. H. CHASE 'SIGNAL Filed Sept. .15, 1935 e Sheets-Sheet 2 June a, 1937. R H, HASE 2,082,789

' SIGNAL Filed Sept. 15, 1933 6 Sheets-Shee't :5

June 8, 1937 P. H. CHASE I 2,082,789

SIGNAL Filed Sept. 15, 1935 e sheets-sheet 4 June 8, 1937.

"FIG. l3. FIG. l4.

* P. H. CHASE SIGNAL- Filed se k 15, 195:5

6 Sheets-Sheet 5 FIG. I?

FIG. l8

5 x90 90 mp] a 5 c p, I r 19/ 1 I90 42/ L1 2422 2x432 70- 92- I r\ (I e June 8, 1937. r P. H. CHASE 8 'sxqmu.

Filedsept. l5, 1933 v 6 Sheets-Sheet 6 FIG. l9.

FIGZO. 5 .1 i5 90 37 T?" M l if Patented June 8, 1937 VNITED; STATES PATENT OFFICE f aoaavsa SIGNAL ram in. Chase, Bala Cynw'yd, Pa. Application September 15, 1933, "Serial No. 689,556 10 Claims. (Cl. 171-311) This invention relates to a light signal system.

out opening the signal circuit; the provision of a pilot lamp which indicates the operation and condition of the system; the provision of avariably modulated light signal; the provision of eifective' 15 signal lamp operation in the event of bum-out of the pilot lamp and/or the stoppage of certain of the apparatus; and the provision of a multiplepurpose system wherein a single lamp affords illumination and a signal. Other objects will be in 20 part obvious and inpart pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of,

construction, and arrangements of parts which will be exemplified in the structure and circuits 25 hereinafter descri and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which are illustrated several of various possible embodi- 30 ments of the invention,

Fig. l is a diagrammatic layout of one form of the invention;

Figs. 2 to 8 show modifications of the form of the invention shown in Fig. 1; 1 3 Fig. 9 shows a form of the invention in which an impulse transformer and a contactor are combined; Fig. 10 shows a form of the invention similar to that shown in Flg. 6 but shows opposed action 10 of certain secondary series coils;

Fig. 11 shows amodified energizing method;

'12 show a modification in which mechanical means is used for sho circulting a magnetic circuit;

. Fig. 13 is a diagrammatic side, elevation of certain core parts of Fig. 12;

Fig. 14 is a detail of another iorm of core parts.

of'Fig. 12;

Fig. 15 is a side elevation of Fig. 14; n Fig. 16 is a plan view of a modified form of armature and core parts;

of Fig. 16;

. Fig. 18 illustrates another ,form of the inven- 5 tion', broadly considered; 2

. Fig. 17 is a. vertical section taken on line |'|-l l Fig. 19 illustrates a modification in which energy transfer is eflfected by methods alternatively to those shown i Figs. 1 to 18; and,

Fig. 20 illustrates a modification of the structure of Fig. 19 in which a modulation is effected 5 by. energy withdrawal instead of by energy addition as in said Fig. 19.

Similar reference characters indicate corresponding parts throughout the several views of the drawings. 10

It is known practice to mount on the rear of a motor vehicle an electric stop signal which is lighted upon the application of the brakes,

' by the closing of a switch actuated from the foot brake mechanism. It thus gives a signal often 15 anticipatory of the slowing and complete stopping of the vehicle. Such a stop" light signal is usually contained in or adjacent to the electric rear light housing, oftenzf is the same color as the tail light, and sometimes consists of one ofthe 2o filaments in a two-filament lamp, the other filament being used for the tail light.

Consequently, the eflicacy of the usual stop light signal .is'greatly reduced, particularly at night, because onceit is lighted it is usually unchanging and may be similar in appearance to the tail light. It does not continue to give an unmistakably distinctive signal warning that a vehicle is slowing, stopping, or has stopped.

The practice of signalling left and right turns by hand is little observed and when done, often escapes notice, or is not understood. Such hand signals are usually inconvenient to the driver of a closed vehicle, particularly during inclement weather. Electric direction signals of the usual types are subject to similar diiiiculties as the-stop light.

The provision of means for causing the flickering or blinking of stop and direction light signals may aiford a warning signal different from 40 the tail light, but these results have often been secured at the expense of added complications andliability of complete impairment of operation. of the signal devices, and, among certain other disadvantages, omit means indicating to the. ve-

- hicle driver the operation and condition'oi' the signal system.

The present invention. secures the advantages 01' the signal system.

It is to be understood that the method and apparatus of the present invention is useful in other applications than to vehicles; for example,

on crossing gates, traffic signals, switchboard signals and the like, wherein similar requirements may exist. The vehicle application is used merely by way of example.

Referring now more particularly to Fig. 1, there is illustrated at numeral i an electric signal lamp with filament t, connected by wire ii, in series with coil 5, wire 9@, switch 52 and wire at to a battery Gil. The signal lamp circuit is completed by wires Q2, 99 and it. For example, as applied to a motor vehicle, the signal lamp 5 may be a' six to eight volt tungsten filament automobile type lamp of three to thirty-two rated candle power; the switch 52 may be actuated, for example, by the foot-brake mechanism to close the switch when the brake pedal is depressed in case the signal lamp the switch may be actuated manually in case the signal lamp is for a direction signal; the battery may be the usual lead storage battery, and the 'wire 99 may be replaced by the metal frame oi. the vehicle. I

The series coil 5 having terminals we, we is the secondary winding or coil of an impulse transformer l5 wherein both and a primary coil 8 having terminals W9, lei, are wound on a magnetic iron orsteel core i8. The primary coil 8 is connected across the supply circuit, between wires ilfi and 99, by the wires 91 and 98 in series with the contacts at and 32 of the contactor deviceZfl.

The contactor device 20 recurrently closes and opens the contacts 3| and 32, at a frequency within a suitable range, so that as long as switch 52 remains closed, the primary coil 8 is suecessively energized and tie-energized.

'In the electromagnetic contactor device or vi- 4,0 brator 20 illustrated in Fig. 1, a coil 2! is wound about a magnetic core 22, which is associated with an armature 23 pivoted at 2%, with an extension 25'on which is mounted a weight 26. The armature is normally retracted from the core 22 by a spring 21. A portion of or extension of the armature, 3| is adapted to make contact with contact 33 when the armature is retracted as shown and, when the armature moves toward the core 22, to break the contact with $3 and make contact with contact 3!.

Upon closing of switch 52, in addition to the current passing through wire 90, series coil 5, and wire I! to the signal lamp 9, the current for the shunt coil 2| passes through wire '93, coil 2!, contact 33, armature extension 3|, armature 23 and back to the battery through wires 98, 99 and 92, and the magnetic flux is produced through the core and armature.

By the attraction of to straining force of spring 2'! is overcome, the armature 23 moves downward, contact is broken between armature extensionlii and contact 33, and contact is made between armature extension 38 and contact 32. extension and contact 32 completes the circuit to, the primary coil 8, through wire 91.

Immediately upon the opening of the circuit through coil 2! by the aforesaid-breaking of contact between armature extension 5! and contact 33, the magnetic flux through the core 22 and armature 23 rapidly decreases, the spring 218 retracts the armature, contact is broken between armature extension ill and contacted and the primary coil is de-energiaed, and then centaot is is i e-established between armature extension iii is for a stop" warning, or

the said secondary coilv that change. the armature 23, the re-- The contact between armature and contact 33. Thereupon the circuit connections become the same as at the instant switch 52 was closed, and as long as the switch remains closed this same cycle of operation will take place repeatedly.

The function of the contactor 26 also can be performed by other suitable means. As generally applied to the usual types and sizes of automobile electric lamps, the frequency of closing the contacts should preferably fall between two and ten, per second, because of the relation of persistence of vision and lag in filament incandescence and cooling to desirable variability or modulation of light from the signal lamp, but the frequency for a given signal device need not remain constant and in some embodiments, it may be desirable for it to vary, for example, with the speed of the vehicle.

In the impulse transformer IS, the secondary coil 5 and the primary coil 8 are magnetically closely linked by being wound on the magnetic iron or steel core l8. In this embodiment these two coils preferably are connected with their magnetomotive forces opposing and the ampereturns of the primary coil are at least twice those of the secondary coil, and may be considerably greater than twice. The resistance of the secondary coil is preferably low. It has been found that a secondary coil resistance drop from ten to twenty per cent of this range are permissible.

Upon the closing of the switch 52, current from the battery 60 passes through the series circuit ill, 90, 5, H, the signal lamp l, and wires i8, 99 and 92. If at that time the contacts 3!, 32 are open, the signal lamp current passing through the series or secondary coil 5 causes magnetic flux to build up in the core l8 in a certain direction, hereinafter referred to as the secondary direction, In a small fraction of a second the contactor causes the contacts 3|, 32 to close, current starts to flow through the primary coil 8 and increases at a rapid rate. Because the magneto-motive force of the primary coil is opposed to and greater than that of the secondary coil, the magnetic flux in the core IB rapidly decreases, reverses its direction and increases in that opposite direction, hereinafter called the primary direction. When the contacts 3t, 32 open a fraction of a second later and interrupt the primary coil current, the magn tomotive force of the primary coll disappears and the flux rapidly reverses to the secondary direction.

These changes of flux through the secondary coil induce voltages therein proportional to the rate of change of flux and in a. direction opposing Therefore, while the flux is changing from its secondary direction to its primary direction, there is induced in the secondary coil a voltage aiding the flow of the current through the secondary coil 5 and the signal lamp l. Consequently, during this period of change the voltage impressed upon, and the light emanating from the signal-lamp, are increased. Conversely, while the flux is changing from its primary direction to its secondary direction, there is induced in the secondary coil a voltage opposing the. flow of current through the secondary coil 5 and the signal lamp l and during this latter period of change the voltage impressed upon, and the light emahating from, the signal lamp are decreased.

For convenience, hereinafter the magnetic flux change and induced secondary cell voltage existing during the change of flux from secondary dithe signal circuit voltage is suitable, although considerable deviations from aoeavaasimilarly those existing during the change of flux by from'primary direction to secondary direction may be referred to respectively as the primarysecondary flux change and the primary-secondary voltage.

It is therefore apparent that, for each opening and closing of the ll, 32, there is impressed on the signal lamp circuit through the secondary coil successively an ad- 'ditive voltage impulse and a subtractive impulse which produce corresponding changes to modulate the light from the signal lamp. The order of magnitude of the modulation is indicated by 1 the sum of the primary-secondary and secondary-primary voltage impulses, hereinafter referred to as the swing voltage.

The design and construction of the impulse transformer, its component parts and associate ed apparatus can be varied considerably-in order voltages and to provide the desiredse'cond'ary swing voltage. However, for example; it has been found that an impulse transformer with a we of 1.6 square inch cross-section and 7.5 inches length magnetic path, a series coil of 90 turns No. 16 gauge wire and a primary coiloff 250"tiirns No. 3 20 gauge wire, connected in a 6 volt vehicle signal circuit (illustrated in Hg. 1) will produce a swing voltage of approximately three volts on a signal lamp load of 25 watts, consistingof the usual motor vehicle type tungsten lamp or lamps. The resistance drop through the series coil is: only about one volt and, if desired, can readily be decreased by the use' of larger wire therein. This is advantageous in event of non-operation oi the *contactor.

For various signal lamp loads the desired swing voltage can be secured with an impulse trans? former constructed with appropriate care" dimensions, and boil wire sizes and turns. It is apparent that the brightness varied considerably both above and below normal brightness, that is, the brightness corresponding to the circuit voltage minus the resistance drop through .the series coil. Because the light flux from a tungsten lamp'is a function of the voltage to more than the third power, there can .be secured a large percentvariation of the total light flux from the signal lamp. This variation may be as great as, or greater than, the light flux at normal brightness, depending upon the design of the impulse transformer and its control as hereinafter described.

Th'us, without recurrently interrupting the portion of'the circuit supplying the signal lamp and without introducing therein a substantial resistance drop, a high degree of signal visibility is se-'- cured together with a normal brightness closely approaching the brightness at full signal circuit voltage. In many applications of the invention, these advantages are'secured with a smaller signal lamp than is used with other typesoffsi'g'nals The magnitude. of signal light mod ilation-is largely determined by the magnitude of the swing voltage, which is in turn a function of the rates of change of magnetic flux through the secondary coil 5. In some applications of the invention, it maybe desired to adjust the signal lamp modu latio'ri. or to vary it from time to time manually or automatically. Fig. 1 shows one means for such control comprising a resistor 46 connected 75 in wire 97 of the primary coil circuit. Its resistof the signal, lamp is ance may be fixed or variable and adiusted by external means. a

When the resistance of the resistor is controlled lighting switch, or by the transmission. By such a resistor the swing voltage can be varied from its full value, for the particular impulse transformer and signal lamp load, to a very small per Icentage of theiull value, without changing the lower resistance (for example, larger wire) and thus remilts in a materiallyhigher swing voltage, but"limits or decreases the maximum .value of thecll'i'rent throu h the primary coil. The rate oi increase oi the primary coil current is initial- 1y greater because upon the closing of the con tarn sh-jet. the ballast resistor is relatively cold, andthereiore its resistance is low. As the pri- 'mary coil current increases, .the resistance'of the V increases materially above its initial v's'iue'and relation between. the circuit elements, may be-. come .the predomin'a g element in limiting the primary current. It has been found that a motor-vehicle type tungsten lamp rated 15 or 21 candle" power at 6 volts provides a suitable ballastreslstor l1 fort signal lamp load describedhereinabove.

Ifig. 2 .alsoshows a manual means of control of si'g'n'allamp modulation, connected in parallel with the series coil 5.

The bailast'risi stance ll for a piloi laii'ip, ioi example, located inside a vehicle, toindica'te'to the operator the operation and condition of the signal system, provided it has a filament or wire which heats during the operation cycle'tocmit suiiicient light. lamps, whichfu'nction primarfly, or solely, as pilot lamps, are also illustrated in Fig. 2 at numerals II and I2. Numeral ll indicates a pilot lamp, such; for example, as a rated 3 candle power moto'r vehicle tungsten lamp, connected in parallel withthe series coil 5, and numeral l2 indicates a pilot lamp connected in parallel with the signal lamp.

Asthe contacts 3 l,

p imary circuit, lf-these contacts are-subject to rapid wear .orburning under such duty, the connectiqn' of a. condenser 50 across. the terminals of tfi'e primary coil I (Fig. 1) or across the con (Fig. 2)'is desirable. It has been, found that afcondenser of 0.5 to I micro-farad such, for example, as daylight and or equivalent means,

thus,depending upon the e impulse transformer and a resistance 40 being 7 of Fig. 2 may be used Other 32 make and break the curf rent through the relatively high inductance of the 4- is suitable, for either Fig. 1 or Fig. 2. Contact operation may be further improved, under some conditions, by the inclusion of a .few ohms resistance in the condenser connections.

In Fig. 3' the series resistor 68 is short-circuited periodically by the contacts 3!, 32 of the contactor 20. The resistor 38 preferably. has several times the resistance of the primary coil so that when not short-circuited the current through the primary coil is a small fraction of the current whenresistor dB is short-cir'cuited. There is preferably, though not necessarily, also included a ballast resistor ii in series therewith.

In Fig. 4 the primary coil 8 is connected across the circuit in series with a resistor 49, and the primary coil is periodically short-circuited by the contacts iii, 32 of the contactor device 20. In this embodiment, the resistor 69 preferably has a relatively low resistance compared with the resistor Q8 of Fig. 3, and under some conditions it may be of the negative coeflicient type such, for example, as is afforded by a carbon filament lamp, in which latter case it can also serve as a pilot lamp.

In Fig. 5 two signal lamps 2 and 3 are connected by wires 12 and 13 respectively to series coils and i and these coils connected to coil 8 and wire 90, as illustrated, so that their magnetomotive forces are aiding each other, although they need not have the same number of turns nor be of the same size of wire. The series coils may alternatively be connected with their magnetornotive forces opposing as is illustrated in Fig. 10 and further described hereinaften This embodiment is useful in many situations, for example, when it is desired to apply a different degree of modulation to the two signal lamps, or as illustrated in Fig. 6, to provide for the selection of one of two signal lamps with the minimum of switching changes in the signal lamp circuits.

In Fig. 6 is illustrated control by a manuallyoperated switch 53 such as might, for example, be used in a motor vehicle to indicate left and right turns. The two signal lamps 2 and 3 are connected to separate coils as in Fig. 5, but the series coils are selectively energized, and the primary coil circuit simultaneously energized by means of the double-throw switch 53. In the left position L switch 53 energizes wire I92 through contacts iii, H2, and wire 90 through contacts iii, (I22; and signal lamp 2 is modulated by primary coil 8 acting on series coil 6, the circuit through series coil 7 and lamp 3 being open. In the right position R switch 53 energizes wire 593 through contacts iii, H3 and wire 90 through contacts iZi, E23; and signal lated by primary coil 8 acting on series coil i,- the circuit through series coil 6 and lamp 2 being open.

It is apparent that more than two signal lamps can be operated with the Fig. 5 and Fig. 6 methods, by utilizing an impulse transformer with the appropriate number of series coils and, in the caseof the selective signal operation of Fig. 6, a selector switch similar to switch 53 but having an appropriate number of contacts. It is also apparent that two or more signal lamps in par allel may be operated from each series coil 8 and l, instead of the single lamp illustrated. Such lamps in parallel and therefore controlled and modulated simultaneously may, for example, be mounted on both the front and to indicate left and right turns to trafiic both in 75 front and. in the rear.

lamp 3 is modurear of a vehicle aoeaaso The selective signal lamp operation may also be afiorded with one series coil as illustrated in Fig. '7, instead ofthe two series coils shown in Fig. 6. In Fig. 7 the wire ill from the series coil 5 is connected to wire 12 through switch contacts iii, H2 and thus energizes and modulates signal lamp 2 when switch 53 is in the left position L, and when switch 53 is in the right position R, wire i'H is connected through switch contacts iii, M3 to wire 13 and thusenergizes and modulates signal lamp 3.

Fig. 8 illustrates a signal system which utilizes only one lamp for two purposes, such for example, as a combination tail lamp and stop signal. This embodiment also has the advantage of utilizing only one wire to the dual-purpose lamp. When switch 5G is closed. the signal light current passes through resistor I65, wire 90, series coil 5 and wire H, but no current-passes ,through the primary coil 8 because switch is open. The resistance of resistor M5 is selected so that the signal lamp i burns steadily at reduced voltage, and therefore reduced brightness, but aifords as much light as the usual tail light. When switch 55 is closed, switch 55 and resistor M5 are by-passed through wires I90, l9! and switch contacts 2, M3 and the primary coil is completed through switch contacts 2|2, 2N. The signal lamp i therefore burns at full brightness and provides the modulated signal as hereinabove described as long as switch 55 re mains closed.

If it is desired to have the lamp burn steadily at full brilliancy and also serve for signalling purposes, for example, as a combination cowl lamp, headlight, or mudguard lamp and a direction signal, the resistor N5 of Fig. 8 is omitted.

In Fig. 9 is illustrated an embodiment in which the impulse transformer and a contactor similar to that of Fig. 1 are combined. On an extension 2? of the magnetic core adjacent one end of the windings (coils 8 and 5) armature 23 is pivoted at 26. A branch magnetic core H8 is brought from the side of the main magnetic core [8, preferably adjacent the other end of the windings (coils Q and 5), close to the free end of the armature 23. A portion of or extension of the armature 3i is adapted to make contact with contact 32 when the armature moves toward the branch core. On the branch core are a retardation collar or sleeve I it of copper and a holding coil 9 connected in series with the primary coil 8 and contact 32. Holding coil 9 is connected so that its magnetomotive force acting around the branch core-armature path is in the same direction as that of secondary coil 5.

When switch 52 is closed current passes through the signal lamp circuit including wires 9!, 90,. series coil 5, wire H and signal lamp i.

Some of the magnetic flux set up by series coil 5 passes through the armature 23 and the branch magnetic path H8, and movement of the armature causes contacts 3!, 32 to close and complete the primary coil circuit through wires 90, 91, holding coil 9, armature 23, core l8 and wire 98. Although the magnetomotive force of the primary coil 8 rapidly changes the direction of the magnetic flux in the main core, the magnetomotive force ofthe holding coil 9 also increases and acts .to continue to maintain the flux through the branch core and thus hold the contacts 3|, '32 together for a longer interval. When the magnetomotive force set up by the primary coil sufiiciently decreases the flux through the branch core and armature, the armature is retracted by the springv 29, the contacts ii, 32 separate, the primary coil current is interrupted, the flux in the main core and branch core rapidly reverse tothe secondary direction and another cycle of operation starts. The retardation collar or sleeve to lengthen the cycle of operation but under periodicity of operation can be varied over wide limits by the selection of the number of turns 1 of the holding coil 9 or a shunting resistor 6 can be included to secure the same result more readily, for example, when manual adjustment of modulation frequency is desired. In case the signal lamp burns out or the signal 15 lamp circuit otherwise opens; the contactor will not operate, as under that condition there is no current passing through the series coil. feature is of advantage in indicating the operativeness of the signal system, with a pilot lamp the terminals series coil. The signal system illustrated in Fig. 10 includes two signal lamps 2 and 3, which may be the same or of different sizes, connected by wires 512 and 13 respectively to series coils 1 and 8, which preferably are wound to give substantially equal and opposing magnetomotive forces, The primary coil 8 is energized through the contacts .of the contactor 20 so that the primary coil reversed as the contactor current flow in the other secondary coil. Therefore, when the impulse voltage on one of is useful under many conditions, such for example, asin a vehicle stop" signal, or, as a direction signal. a

In Fig. 11 is illustrated a signal system with the erator |8l is illustrated in parallel with the battery. Separate excitation of the primary coil is 55 advantageous under i 65 late the signal lamp voltage only when the gen- I tery It! may be omitted, and depending upon the 7 voltage regulation characteristics of the gengenerator speed, or may vary with the generator speed.

75 Fig. 12 illustrates an embodiment in which the some conditions may be omitted. 4 The I circuited, while in magnetic 5 primary coil 8 and the series or secondary coil I are placed on separate legs of the magnetic circuit, with .their magneto-motive forces oppming. A magnetic armature 123 periodically shortcircuits the magnetic circuit I 8. The primary coil ampere-turns are preferably at least twice those of the series coil. The short-circuiting armature is actuated by a cam, for example, on a motor vehicle, connected to the engine or transmission, or may be actuated by an electric motor or solenoid.

Fig. 13 :shows (windings omitted) the right side elevation of the magnetic core I 8, the short-circuiting armature 123. cam I28 and cam shaft 126 ofFig. 12. The armature E23 is pivoted at its lower end on the shaft 124 which is supported by the two bearings 121, 121. In the position shown, the two ends of the armature 123 are in contact. with the cross members of the magnetic core and the magnetic flux set up by'each coil 5 and 8 is short-circuited. While the shaft 126 and attached cam rotate 90 in the direction of the arrow, the lobe of the camengages the armature extension and moves the upper end of the armsture out of contact with the magnetic core, as indicated by the dotted magnetic short-circuit. The flux set up by the series coil 5 is rapidly overcome by the greater magnetomotive force of the primary coil 8 and voltage is induced in the secondary-primary direction in the series coil. As the cam rotates further, the cam surface permits the armature, under the pressure of the compression spring 122 and/or the magnetic attraction from the core. to resume its original position in contactwith the core. As this takes place, the series coil flux rapidly re-establishes itself and there is induced therein a voltage in the primary-secondary direction. The modulation frequency is equal to the speed of the cam shaft. Other magnetic short-circuiters will suggest themselves.

In the modification of Figs. 14 and 15 the cylindrical magnetic armature I23 rotates, with a small airgap or no air gap (if the surfaces are lubricated) between the circular faced poles 3l8,

3l9, and the armature end faces formed to conform thereto. In the position illustrated the magnetic circuit between the core legs is shortthe position 90 therefrom (shown dotted) the short circuit has been removed.

Figs. 16 and 17 illustrate another embodiment in which there are two primary core legs and two secondary core legs and a cylindrical rotor disposed therebetween. The two primary core ;legs Sit and 320 are diametrically located and on a diameter 90 therefrom are located the two series core legs 3l9 and 3". The core 2i) magnetically connects and mechanically supporm all four core legs. The inner face of each core leg preferably occupies one-eighth the circumference 0r 5.

shaft 228, rotates between the four circularlygap if the surfaces in contact are lubricated. There are two segment armatures 821 and I29, each of which spans an arc of I35", with a nongap between adjacent edges of 45. Numerals 826 indicate non-magnetic material and/or air space. i

As the rotor turns in the direction of the arrow, it passes the position 45 clockwise from the position illustrated, and the trailing edge of armature 82'! breaks the magnetic path between primary core leg 3l8 and series coil leg 3|! and the lines, thus removing the The. cylindrical rotor 825, mounted on leading edge establishes a magnetic path: between primary core leg 318 and series core leg 32I. Simultaneously, the trailing edge of armature 829 breaks the magnetic path between primary core legs 320 and series core leg 32l and the leading edge establishes a magnetic path between primary core leg320 and series core leg 389.

The primary coils on core legs Me and 820 are preferably wound of opposite polarity, that is, so that the flux through core leg 3I8 passes into the rotor and the flux through core leg 320 passes out of the rotor or vice versa. Then the flux through each series core leg M9 and 32! reverses at the above 45 position of the rotor and at every quarter-revolution position therefrom. Preferably, each series core leg is wound with two coils of equal and opposing magnetomotive force and the coils on cores are and 32I which have the same instantaneous polarity may be connected in Series or in parallel. Thus, depending upon the number, size and other characteristics, there may be two or four signal lamps modulated thereby similarly to the results secured by the embodi ment of Fig. 10, for example, and the modulation frequency is twice the shaft speed.

Fig. 18 illustrates an embodiment with impulse transformer in which the signal lamp I serves as a stop signal, and as a left" and right" direction signal. The primary coil current is supplied through four spring distributor contacts 8!, 82, 83, and 84 set .at 90 intervals about a one-lobed cam 85 mounted on a shaft 8'6 rotated, for example, by the engine or the transmission, and at constant speed or variable speed. When switch 52, actuated by the foot brake mechanism, is closed, the signal lamp l is energized through wire 90, series ("ill 5 and wire H. Simultaneously the shaft M and cam 86, both relatively insulated from the frame of the vehicle, are energized from. wire 90 through wire I90 and brush 80. During every 90 of each revolution .of the cam it makes contact and breaks contact successively with spring contacts M, 82, t3 and at. As long as switch 51 is in its middle position (as illustrated) 'all these four contact springs are connected to wire 91 so that, during each contact of the cam with each of the four springs, the primary coil circuit is completed through wire 91, primary coil 3 and wire 90, and then is broken a short time thereafter. Consequently the signal lamp is modulated. as hereinabove explained in detail, above and then below normal brightness for each such primary coil circuit make and break, and these modulations recur at uniform time intervals, thus:-

HL-I-IL-I-U.rHL-I-IL-HL-, etc. where indicates a period of normal brightness, (H) indicates a period of'brightness above normal and (L) indicates a, period of brightness below normal.

When switch 51, manually controlled by the operator, is thrown to the left (for example, to

- signal a left turn) brush 80 is energized through wire I9I, switch contacts 42 I 422 and wire I90, the connection from the spring 82 to wire 91 is broken by the opening of contacts 4'I I, .4I2 (switch contacts 43I, 432 remain closed) and consequently in each revolution of the cam 86, one of the four possible signal lamp modulations is eliminated and the following signal lamp modulation program takes place:- HL-I-II.I-HL I-ILHL- HL L 1-II.|-HI.|-HL etc. When switch 51 is thrown to the right (for drop therethrou'gh.

- lamp under example, to signal aright turn), brush 80 is energized through wire I9I, switch contacts 42I,

423 and wire I90, the connection from both springs 82 and 83 to wire 91 are broken by the opening of contacts 4, M2 and 43I, 432 and consequently in each revolution of the cam 86, two of the four possible signallamp modulations are eliminated and the following signal lamp modulation program takes place:-

HI.|HL HI.|HL

HL-HL etc.

It is apparent that by this apparatus, there are produced at will, three distinct signal lamp indications, and that by appropriate additional spring contacts acted upon by cam 86 and by appropriate changes to the switch 51, other signals may be produced in diiferent combinations andthe desired results secured.

In Fig. 19 is illustrated a signal system in which there is modulating energy transfer between the signal lamp current and the source of electrical energy without the energy transfer therebetween being through a series coil in the signal lamp circuit. Under some circumstances, this alternative method has advantages, as will be apparent hereinafterx In series with the signal lamp i is a oneway electric valve 2M, such for example, as a copper oxide-copper rectifier, and a resistor I40 in series. This valve is connected so that the signal lamp current from the battery 60 will pass through it but substantially no current can pass in the opposite direction. The resistor I40 may be omitted in case the resistance of the valve alone is sufiicient and in case no variable modulation effect afforded by the resistor is desired. Alternatively, under some conditions the valve 24I may be omitted. An auxiliary battery 62 is in series with the contacts 3i, 32 of the contactor 20 and in parallel with (shunting) valve 2M and resistor I40, and is connected so that its voltage aids or adds to that of the main battery (iii. The contactor 20 may be the type illustrated in Fig. 1 or other suitable means which closes the contacts 3 I, 32 at a suitable modulation frequency, as hereinabove described.

When switch 52 is closed, and contacts 3!, 32 are open, the signal lamp current passes through valve 2M and resistor I40, and the voltage on the signal lamp is the voltage of battery 60 less "the The total resistance of the valve and/or resistor may signal lamp brightness is only little or substantially less (but still distinctly visible) than if the valve and resistor were omitted. After a fraction of a second, contacts 3 i, battery 62 in series with and aiding the main battery 60, thus increasing the voltage on the signal lamp to the sum of the two battery voltages and increasing its brightness above that corresponding to the full main battery voltage. If the valve is omitted, the current through battery 62 is the algebraic sum of the signal lamp current and of the current through the resistor, but if, as is preferable, thevalve is included, the current therethrough is only that of the signal the total voltage.

For example, it has been found on a signal lamp circuit, such as is usually employed on an automobile, that with a 6-volt battery 60, a 21 candle power (r-8 volt tungsten lamp, an auxiliary battery voltage of 2 volts and a valve and resistor of 1.2 ohms total resistance or less,there is a modulation which affords a distinctive signal.

In the shunting or parallel circuit is also in-.

be of such value that 32 close and connect the modulation produced by the auxllllgy battery or generator.

A direct-current generator IN is illustrated in parallel with the auxiliary battery, but may be replace of the generator.

ot lamp H is included in the embodiment A pl] of Fig. 19, for example, in parallel with resistor I40 and valve 2, and numeral (2 indicates a pilot lamp connected in parallel with the signal lamp.

40 By this apparatus there is secured modulation Fig. 1 or other suitable means which closes the cflntacts modulation frequency, as herein described. Also, there is included in the shunting path an electric valve 2. preferably of considerably lower resistance than 'theresistance of coil 205, and connected so that the signal lamp current from the battery 60 will u pass through it but substantially no current can pass in the opposite direction. This valve 2 is not, however, absolutely necessary. When switch 52 is closed and contacts 3|, 32 are open, the increase of the signal lamp current to its full value determined by the total resistance in the circuit is delayed for a short interval by the counter-electromotive force induced from the building up of the flux in the magnetic core ll of the inductance "5. Therefore, the voltage drop across inductance coil 205 for that short interval is greater than the resistance drop thereacross and the signal lamp is modulated below the amount corresponding to the resistance drop only 5 therethrough.

After a fraction of a second, contacts 3|, 32 close and shunt or short-circuit the inductance coil and substantially the greater portion of the signal lamp current passes direct from wire to wire H through the shunting path comprising contacts 3|, 32 instead of through the inductance- I coil 285. The energy of the magnetic field tends 3!, 32, in a direction opposite to the flow therepressed because the energy of the magnetic field is dissipated in the short-circuit path instead of being substantially returned to the signal circuit when the valve is included. Pilot lamps are included in the embodiment of 35 Fig. 20, across the terminals of the inductance In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. 50 As many changes could be made in carrying out the above constructions without departing from the scope of the invention, it is intended that all shown in the accompanying drawings shall be 55 interpreted as illustrative and not in a limiting sense.

I claim:

1. A signalling system comprising an electric. signal circuit, electric signal therein, a secondary coil in series with said signal, said source of current energizing the signal to a predetermined signal strength by means of a predetermined voltage, and a magnetic circuit with which said coil is 65 linked, means for periodically changing the flux through said magnetic circuit to cause an efiect inclusive of a counter-electromotlve force in the circuit, said last-named means comprising a pria source of current therein, an 60 .electromagnetically cooperating with said secondary winding to effect an aiding electromotive and a counter-eiectromotive force in the signal circuit to respectively increase and reduce the strength of the signal, said primary coil be-' ing connected across said electric circuit, a makeand-break contact in series with said primary winding, and electromagnetic means adapted to automatically operate said make-and-break contact and energized from said source of energy, said predetermined voltage of the source being sufficient to restore the signal to predetermined strength upon the disappearance of said counterelectromotive force and upon the consequent reestablishment of the source voltage in the signal circuit.

3. A signal circuit comprising signal means, an impulse transformer, a secondarywinding-on said transformer and in series with said signal means, energizing means of predetermined voltage, an electric circuit connecting said secondary winding to the energizing and signal means, said energizing means being adapted to initiate signal operation at said voltage, a primary winding on said impulse transformer electromag- ..netically cooperating with said secondary winding and energized from said energizing means to set up an opposite transformer flux, and means periodically to vary said energization to effect both aidingin the circuit.

4. A signal circuit comprising signal means operating normally at a predetermined voltage,

an impulse transformer, a secondary winding on said transformer and in series with. said signal means, electric energizing means of predetermined voltage, means for connecting said electric energizing means with said secondary wind ing to operate the signal means normally at said predetermined voltage, a primary winding on said impulse transformer electromagnetically cooperating with said secondary winding to apply a counter-electromotive force to the signal circuit, and means adapted to periodically vary the flow of current through said primary winding, said predetermined voltage of the source being sufllcient to restore the signal to original strength upon the disappearance of said counterelectromotive force and upon the consequent reestablishment of the source voltage in the signal circuit.

5. A direct current signalling system comprising a signal circuit, an electric signal therein comprising an incandescent-filament lamp, energizing means in the circuit for initiating energization of the lamp, a coil in series with said lamp, a transformer having a magnetic circuit with which said coil is linked, and means for periodically changing the flux through said magnetic circuit to apply at least a counter-electromotive force to the circuit, said last-named means comprising a primary coil linked with said flux path and means for variably energizing said primary coil.

6. In a signal system, ondary coil and an energy a signal means, a secsource of predeter- 7 mined voltage both in series therewith, said and counter-electromotive forces source normally energizing said signal means at said voltage, a flux path linked with said coil, a primary coil also linked with said flux path and adapted to effect a counter-electromotive force to the signal means, and means adaptedperiodically to open and close a circuit tog-said primary coil, said voltage of the source being ,7

sufilcient to return the signal means to normal energization upon disappearance of said counter-electromotive force.

7. Ina signaling system, an electric signal, a coil connected in series with said signal, a transformer having a magnetic circuit linked-with said series coil, a source of energy having a voltage adapted to normally initiate the signal, a signal circuit connecting the signal with the series coil and source of energy, a primary coil linked with said magnetic circuit and connected across the electric circuit, means for periodically changing the primary coil connection and thus the flux characteristics of the magnetic circuit, whereby modulation is effected of energy transferred between the source of energy and said signal means, the primary coil applying a repeated counter-electromotive .force to the signal circuit, the voltage of the source being adapted to energize the signal normally when the counter-electromotive force is at a minimum.

8. In a signal system, a signal, a secondary winding and a source of energy having a voltage adapted to normally initiate the signal serially connected in a main signal circuit, a primary winding, 9. flux path interlinking' said secondary and primary windings, said primary winding being connected to be variably energized fromsaid source of energy, said ing periodically applying a counter-electrometive force to said main circuit whereby the signal voltage is modulated with respect to the voltage of the energy source.

9. In a signal system, asignal, a secondary winding and a source of energy operating at predetermined voltage serially connected in a main circuit, a primary winding, a flux path interlinking said secondary and primary windings, and means for periodically transferring energy between said primary and secondary windings whereby the signal voltage is modulated above and below the voltage of the energy source, the voltage of the energy source being adapted to energize the signal at source voltage after modulation of voltage below that of the source and before modulation above that of the source.

10. In a signal system, a signal, a secondary winding and a source of energy operating at predetermined voltage serially connected in a main circuit, a primary winding connected across said main circuit, a transformer forming a flux path interlinking said secondary and primary windings, and means for periodlcally'transferring energy between said primary and secondary windings whereby the signal voltage is modulated above and below the voltage of the energy source,

primary windf 

